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Message-ID: <CANMq1KBNz7u0XHQBwmJjLbXyT0twxnfFJ7Hn1Cp8HmnKdOdduw@mail.gmail.com>
Date: Tue, 11 Aug 2015 18:52:22 +0800
From: Nicolas Boichat <drinkcat@...omium.org>
To: leilk.liu@...iatek.com
Cc: Mark Brown <broonie@...nel.org>,
Mark Rutland <mark.rutland@....com>,
devicetree@...r.kernel.org, Sascha Hauer <s.hauer@...gutronix.de>,
linux-kernel@...r.kernel.org, linux-spi@...r.kernel.org,
linux-mediatek@...ts.infradead.org,
Matthias Brugger <matthias.bgg@...il.com>,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [v5,2/3] spi: mediatek: Add spi bus for Mediatek MT8173
Hi Leilk,
On Fri, Aug 7, 2015 at 3:19 PM, <leilk.liu@...iatek.com> wrote:
> This patch adds basic spi bus for MT8173.
>
> Signed-off-by: Leilk Liu <leilk.liu@...iatek.com>
>
> ---
> Change in this patch:
> 1. change "pad-select" to "mediatek,pad-select".
> 2. modify clk relevant implement.
> ---
> drivers/spi/Kconfig | 9 +
> drivers/spi/Makefile | 1 +
> drivers/spi/spi-mt65xx.c | 749 +++++++++++++++++++++++++++++++
> include/linux/platform_data/spi-mt65xx.h | 22 +
> 4 files changed, 781 insertions(+)
> create mode 100644 drivers/spi/spi-mt65xx.c
> create mode 100644 include/linux/platform_data/spi-mt65xx.h
>
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 0cae169..38ddfba 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -326,6 +326,15 @@ config SPI_MESON_SPIFC
> This enables master mode support for the SPIFC (SPI flash
> controller) available in Amlogic Meson SoCs.
>
> +config SPI_MT65XX
> + tristate "MediaTek SPI controller"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + help
> + This selects the MediaTek(R) SPI bus driver.
> + If you want to use MediaTek(R) SPI interface,
> + say Y or M here.If you are not sure, say N.
> + SPI drivers for Mediatek MT65XX and MT81XX series ARM SoCs.
> +
> config SPI_OC_TINY
> tristate "OpenCores tiny SPI"
> depends on GPIOLIB || COMPILE_TEST
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 1154dba..9746beb2 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -48,6 +48,7 @@ obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o
> obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o
> obj-$(CONFIG_SPI_MPC52xx_PSC) += spi-mpc52xx-psc.o
> obj-$(CONFIG_SPI_MPC52xx) += spi-mpc52xx.o
> +obj-$(CONFIG_SPI_MT65XX) += spi-mt65xx.o
> obj-$(CONFIG_SPI_MXS) += spi-mxs.o
> obj-$(CONFIG_SPI_NUC900) += spi-nuc900.o
> obj-$(CONFIG_SPI_OC_TINY) += spi-oc-tiny.o
> diff --git a/drivers/spi/spi-mt65xx.c b/drivers/spi/spi-mt65xx.c
> new file mode 100644
> index 0000000..4676b01
> --- /dev/null
> +++ b/drivers/spi/spi-mt65xx.c
> @@ -0,0 +1,749 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: Leilk Liu <leilk.liu@...iatek.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
Since you are using readl/writel, please import linux/io.h as well (it
is implicitly imported by spi/spi.h, but better be safe...)
> +#include <linux/ioport.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/platform_data/spi-mt65xx.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/spi/spi.h>
> +
> +#define SPI_CFG0_REG 0x0000
> +#define SPI_CFG1_REG 0x0004
> +#define SPI_TX_SRC_REG 0x0008
> +#define SPI_RX_DST_REG 0x000c
> +#define SPI_TX_DATA_REG 0x0010
> +#define SPI_RX_DATA_REG 0x0014
> +#define SPI_CMD_REG 0x0018
> +#define SPI_STATUS0_REG 0x001c
> +#define SPI_PAD_SEL_REG 0x0024
> +
> +#define SPI_CFG0_SCK_HIGH_OFFSET 0
> +#define SPI_CFG0_SCK_LOW_OFFSET 8
> +#define SPI_CFG0_CS_HOLD_OFFSET 16
> +#define SPI_CFG0_CS_SETUP_OFFSET 24
> +
> +#define SPI_CFG1_CS_IDLE_OFFSET 0
> +#define SPI_CFG1_PACKET_LOOP_OFFSET 8
> +#define SPI_CFG1_PACKET_LENGTH_OFFSET 16
> +#define SPI_CFG1_GET_TICK_DLY_OFFSET 30
> +
> +#define SPI_CFG1_CS_IDLE_MASK 0xff
> +#define SPI_CFG1_PACKET_LOOP_MASK 0xff00
> +#define SPI_CFG1_PACKET_LENGTH_MASK 0x3ff0000
> +
> +#define SPI_CMD_ACT_OFFSET 0
> +#define SPI_CMD_RESUME_OFFSET 1
> +#define SPI_CMD_CPHA_OFFSET 8
> +#define SPI_CMD_CPOL_OFFSET 9
> +#define SPI_CMD_TXMSBF_OFFSET 12
> +#define SPI_CMD_RXMSBF_OFFSET 13
> +#define SPI_CMD_RX_ENDIAN_OFFSET 14
> +#define SPI_CMD_TX_ENDIAN_OFFSET 15
It feels error-prone that you are defining these offsets here, then
redefining the bits just below.
Looking at the code, I think it's better if you remove these
SPI_CMD_*_OFFSET defines, and only use the BIT(x) defines below.
> +#define SPI_CMD_RST BIT(2)
> +#define SPI_CMD_PAUSE_EN BIT(4)
> +#define SPI_CMD_DEASSERT BIT(5)
> +#define SPI_CMD_CPHA BIT(8)
> +#define SPI_CMD_CPOL BIT(9)
> +#define SPI_CMD_RX_DMA BIT(10)
> +#define SPI_CMD_TX_DMA BIT(11)
> +#define SPI_CMD_TXMSBF BIT(12)
> +#define SPI_CMD_RXMSBF BIT(13)
> +#define SPI_CMD_RX_ENDIAN BIT(14)
> +#define SPI_CMD_TX_ENDIAN BIT(15)
> +#define SPI_CMD_FINISH_IE BIT(16)
> +#define SPI_CMD_PAUSE_IE BIT(17)
> +
> +#define MTK_SPI_QUIRK_PAD_SELECT 1
> +/* Must explicitly send dummy Tx bytes to do Rx only transfer */
> +#define MTK_SPI_QUIRK_MUST_TX 1
> +
> +#define MT8173_SPI_MAX_PAD_SEL 3
> +
> +#define MTK_SPI_IDLE 0
> +#define MTK_SPI_PAUSED 1
> +
> +#define MTK_SPI_MAX_FIFO_SIZE 32
> +#define MTK_SPI_PACKET_SIZE 1024
> +
> +struct mtk_spi_compatible {
> + u32 need_pad_sel;
> + u32 must_tx;
Since the quirks are true/false, define these as bool, and remove
MTK_SPI_QUIRK_PAD_SELECT/MTK_SPI_QUIRK_MUST_TX. Move the comment here
too.
> +};
> +
> +struct mtk_spi {
> + void __iomem *base;
> + u32 state;
> + u32 pad_sel;
> + struct clk *spi_clk, *parent_clk;
> + struct spi_transfer *cur_transfer;
> + u32 xfer_len;
> + struct scatterlist *tx_sgl, *rx_sgl;
> + u32 tx_sgl_len, rx_sgl_len;
> + const struct mtk_spi_compatible *dev_comp;
> +};
> +
> +static const struct mtk_spi_compatible mt6589_compat = {
> + .need_pad_sel = 0,
> + .must_tx = 0,
> +};
> +
> +static const struct mtk_spi_compatible mt8135_compat = {
> + .need_pad_sel = 0,
> + .must_tx = 0,
> +};
You don't need to set these explicitly to 0/false.
> +
> +static const struct mtk_spi_compatible mt8173_compat = {
> + .need_pad_sel = MTK_SPI_QUIRK_PAD_SELECT,
> + .must_tx = MTK_SPI_QUIRK_MUST_TX,
Then you can set those as "true".
> +};
> +
> +/*
> + * A piece of default chip info unless the platform
> + * supplies it.
> + */
> +static const struct mtk_chip_config mtk_default_chip_info = {
> + .rx_mlsb = 1,
> + .tx_mlsb = 1,
> + .tx_endian = 0,
> + .rx_endian = 0,
> +};
> +
> +static const struct of_device_id mtk_spi_of_match[] = {
> + { .compatible = "mediatek,mt6589-spi", .data = (void *)&mt6589_compat },
> + { .compatible = "mediatek,mt8135-spi", .data = (void *)&mt8135_compat },
> + { .compatible = "mediatek,mt8173-spi", .data = (void *)&mt8173_compat },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, mtk_spi_of_match);
> +
> +static void mtk_spi_reset(struct mtk_spi *mdata)
> +{
> + u32 reg_val;
> +
> + /* set the software reset bit in SPI_CMD_REG. */
> + reg_val = readl(mdata->base + SPI_CMD_REG);
> + reg_val |= SPI_CMD_RST;
> + writel(reg_val, mdata->base + SPI_CMD_REG);
> +
> + reg_val = readl(mdata->base + SPI_CMD_REG);
> + reg_val &= ~SPI_CMD_RST;
> + writel(reg_val, mdata->base + SPI_CMD_REG);
> +}
> +
> +static void mtk_spi_config(struct mtk_spi *mdata,
> + struct mtk_chip_config *chip_config)
> +{
> + u32 reg_val;
> +
> + reg_val = readl(mdata->base + SPI_CMD_REG);
> +
> + /* set the mlsbx and mlsbtx */
> + reg_val &= ~(SPI_CMD_TXMSBF | SPI_CMD_RXMSBF);
> + reg_val |= (chip_config->tx_mlsb << SPI_CMD_TXMSBF_OFFSET);
> + reg_val |= (chip_config->rx_mlsb << SPI_CMD_RXMSBF_OFFSET);
> +
> + /* set the tx/rx endian */
> + reg_val &= ~(SPI_CMD_TX_ENDIAN | SPI_CMD_RX_ENDIAN);
> + reg_val |= (chip_config->tx_endian << SPI_CMD_TX_ENDIAN_OFFSET);
> + reg_val |= (chip_config->rx_endian << SPI_CMD_RX_ENDIAN_OFFSET);
> +
> + /* set finish and pause interrupt always enable */
> + reg_val |= SPI_CMD_FINISH_IE | SPI_CMD_PAUSE_EN;
> +
> + /* disable dma mode */
> + reg_val &= ~(SPI_CMD_TX_DMA | SPI_CMD_RX_DMA);
> +
> + /* disable deassert mode */
> + reg_val &= ~SPI_CMD_DEASSERT;
> +
> + writel(reg_val, mdata->base + SPI_CMD_REG);
> +
> + /* pad select */
> + if (mdata->dev_comp->need_pad_sel)
> + writel(mdata->pad_sel, mdata->base + SPI_PAD_SEL_REG);
> +}
> +
> +static int mtk_spi_prepare_hardware(struct spi_master *master)
> +{
> + struct spi_transfer *trans;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> + struct spi_message *msg = master->cur_msg;
> + int ret;
> +
> + ret = clk_prepare_enable(mdata->spi_clk);
> + if (ret < 0) {
> + dev_err(&master->dev, "failed to enable clock (%d)\n", ret);
> + return ret;
> + }
> +
> + trans = list_first_entry(&msg->transfers, struct spi_transfer,
> + transfer_list);
> + if (trans->cs_change == 0) {
!trans->cs_change
> + mdata->state = MTK_SPI_IDLE;
> + mtk_spi_reset(mdata);
> + }
> +
> + return ret;
> +}
> +
> +static int mtk_spi_unprepare_hardware(struct spi_master *master)
> +{
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + clk_disable_unprepare(mdata->spi_clk);
> +
> + return 0;
> +}
In this case, prepare_hardware/unprepare_hardware is redundant with
pm_runtime (apart from the cs_change check, possibly).
If PM_RUNTIME is disabled, leave the clock enabled all the time, if
not enable/disable in pm_runtime functions (as you already do)
See https://git.kernel.org/cgit/linux/kernel/git/broonie/spi.git/commit/?id=db91841b58f9ad0ecbb81ed0fa496c3a1b67fd63
"spi/omap100k: Convert to runtime PM" for an example (it's one of the
last driver that used prepare/unprepare calls, and got converted to
pm_runtime)
> +static int mtk_spi_prepare_message(struct spi_master *master,
> + struct spi_message *msg)
> +{
> + u32 reg_val;
> + u8 cpha, cpol;
> + struct mtk_chip_config *chip_config;
> + struct spi_device *spi = msg->spi;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + cpha = spi->mode & SPI_CPHA ? 1 : 0;
> + cpol = spi->mode & SPI_CPOL ? 1 : 0;
> +
> + reg_val = readl(mdata->base + SPI_CMD_REG);
> + reg_val &= ~(SPI_CMD_CPHA | SPI_CMD_CPOL);
> + reg_val |= (cpha << SPI_CMD_CPHA_OFFSET);
> + reg_val |= (cpol << SPI_CMD_CPOL_OFFSET);
This can actually be simplified a bit by using
SPI_CMD_CPHA/SPI_CMD_CPOL instead.
> + writel(reg_val, mdata->base + SPI_CMD_REG);
> +
> + chip_config = spi->controller_data;
> + if (!chip_config) {
> + chip_config = (void *)&mtk_default_chip_info;
> + spi->controller_data = chip_config;
> + }
> + mtk_spi_config(mdata, chip_config);
> +
> + return 0;
> +}
> +
> +static void mtk_spi_set_cs(struct spi_device *spi, bool enable)
> +{
> + u32 reg_val;
> + struct mtk_spi *mdata = spi_master_get_devdata(spi->master);
> +
> + reg_val = readl(mdata->base + SPI_CMD_REG);
> + if (!enable)
> + reg_val |= SPI_CMD_PAUSE_EN;
> + else
> + reg_val &= ~SPI_CMD_PAUSE_EN;
> + writel(reg_val, mdata->base + SPI_CMD_REG);
> +}
> +
> +static void mtk_spi_prepare_transfer(struct spi_master *master,
> + struct spi_transfer *xfer)
> +{
> + u32 spi_clk_hz, div, high_time, low_time, holdtime,
> + setuptime, cs_idletime, reg_val = 0;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + spi_clk_hz = clk_get_rate(mdata->spi_clk);
> + if (xfer->speed_hz < spi_clk_hz / 2)
> + div = DIV_ROUND_UP(spi_clk_hz, xfer->speed_hz);
> + else
> + div = 1;
> +
> + high_time = (div + 1) / 2;
> + low_time = (div + 1) / 2;
> + holdtime = (div + 1) / 2 * 2;
> + setuptime = (div + 1) / 2 * 2;
> + cs_idletime = (div + 1) / 2 * 2;
Why setting variables with the exact same value? Can you do with just 2?
> + reg_val |= (((high_time - 1) & 0xff) << SPI_CFG0_SCK_HIGH_OFFSET);
> + reg_val |= (((low_time - 1) & 0xff) << SPI_CFG0_SCK_LOW_OFFSET);
> + reg_val |= (((holdtime - 1) & 0xff) << SPI_CFG0_CS_HOLD_OFFSET);
> + reg_val |= (((setuptime - 1) & 0xff) << SPI_CFG0_CS_SETUP_OFFSET);
Not sure of the details, but can you guarantee this will never
overflow? I.e. can div be larger than 256?
> + writel(reg_val, mdata->base + SPI_CFG0_REG);
> +
> + reg_val = readl(mdata->base + SPI_CFG1_REG);
> + reg_val &= ~SPI_CFG1_CS_IDLE_MASK;
> + reg_val |= (((cs_idletime - 1) & 0xff) << SPI_CFG1_CS_IDLE_OFFSET);
> + writel(reg_val, mdata->base + SPI_CFG1_REG);
> +}
> +
> +static void mtk_spi_setup_packet(struct spi_master *master)
> +{
> + u32 packet_size, packet_loop, reg_val;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + packet_size = min_t(unsigned, mdata->xfer_len, MTK_SPI_PACKET_SIZE);
u32 instead of unsigned.
> + packet_loop = mdata->xfer_len / packet_size;
> +
> + reg_val = readl(mdata->base + SPI_CFG1_REG);
> + reg_val &= ~(SPI_CFG1_PACKET_LENGTH_MASK + SPI_CFG1_PACKET_LOOP_MASK);
Use |, not +.
> + reg_val |= (packet_size - 1) << SPI_CFG1_PACKET_LENGTH_OFFSET;
> + reg_val |= (packet_loop - 1) << SPI_CFG1_PACKET_LOOP_OFFSET;
Can packet_loop be >256?
> + writel(reg_val, mdata->base + SPI_CFG1_REG);
> +}
> +
> +static void mtk_spi_enable_transfer(struct spi_master *master)
> +{
> + int cmd;
u32
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + cmd = readl(mdata->base + SPI_CMD_REG);
> + if (mdata->state == MTK_SPI_IDLE)
> + cmd |= 1 << SPI_CMD_ACT_OFFSET;
> + else
> + cmd |= 1 << SPI_CMD_RESUME_OFFSET;
> + writel(cmd, mdata->base + SPI_CMD_REG);
> +}
> +
> +static int mtk_spi_get_mult_delta(int xfer_len)
xfer_len is a u32, so should be mult_delta.
> +{
> + int mult_delta;
> +
> + if (xfer_len > MTK_SPI_PACKET_SIZE)
> + mult_delta = xfer_len % MTK_SPI_PACKET_SIZE;
> + else
> + mult_delta = 0;
> +
> + return mult_delta;
> +}
> +
> +static void mtk_spi_update_mdata_len(struct spi_master *master)
> +{
> + int mult_delta;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + if (mdata->tx_sgl_len && mdata->rx_sgl_len) {
> + if (mdata->tx_sgl_len > mdata->rx_sgl_len) {
> + mult_delta = mtk_spi_get_mult_delta(mdata->rx_sgl_len);
> + mdata->xfer_len = mdata->rx_sgl_len - mult_delta;
> + mdata->rx_sgl_len = mult_delta;
> + mdata->tx_sgl_len -= mdata->xfer_len;
> + } else {
> + mult_delta = mtk_spi_get_mult_delta(mdata->tx_sgl_len);
> + mdata->xfer_len = mdata->tx_sgl_len - mult_delta;
> + mdata->tx_sgl_len = mult_delta;
> + mdata->rx_sgl_len -= mdata->xfer_len;
> + }
> + } else if (mdata->tx_sgl_len) {
> + mult_delta = mtk_spi_get_mult_delta(mdata->tx_sgl_len);
> + mdata->xfer_len = mdata->tx_sgl_len - mult_delta;
> + mdata->tx_sgl_len = mult_delta;
> + } else if (mdata->rx_sgl_len) {
> + mult_delta = mtk_spi_get_mult_delta(mdata->rx_sgl_len);
> + mdata->xfer_len = mdata->rx_sgl_len - mult_delta;
> + mdata->rx_sgl_len = mult_delta;
> + }
> +}
> +
> +static void mtk_spi_setup_dma_addr(struct spi_master *master,
> + struct spi_transfer *xfer)
> +{
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + if (mdata->tx_sgl)
> + writel(cpu_to_le32(xfer->tx_dma), mdata->base + SPI_TX_SRC_REG);
> + if (mdata->rx_sgl)
> + writel(cpu_to_le32(xfer->rx_dma), mdata->base + SPI_RX_DST_REG);
> +}
> +
> +static int mtk_spi_fifo_transfer(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + int cnt, i;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + mdata->cur_transfer = xfer;
> + mdata->xfer_len = xfer->len;
> + mtk_spi_prepare_transfer(master, xfer);
> + mtk_spi_setup_packet(master);
> +
> + if (xfer->len % 4)
> + cnt = xfer->len / 4 + 1;
> + else
> + cnt = xfer->len / 4;
> +
> + for (i = 0; i < cnt; i++)
> + writel(*((u32 *)xfer->tx_buf + i),
This will access past the end of tx_buf if len%4 > 0.
> + mdata->base + SPI_TX_DATA_REG);
> +
> + mtk_spi_enable_transfer(master);
> +
> + return 1;
> +}
> +
> +static int mtk_spi_dma_transfer(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + int cmd;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + mdata->tx_sgl = NULL;
> + mdata->rx_sgl = NULL;
> + mdata->tx_sgl_len = 0;
> + mdata->rx_sgl_len = 0;
> + mdata->cur_transfer = xfer;
> +
> + mtk_spi_prepare_transfer(master, xfer);
> +
> + cmd = readl(mdata->base + SPI_CMD_REG);
> + if (xfer->tx_buf)
> + cmd |= SPI_CMD_TX_DMA;
> + if (xfer->rx_buf)
> + cmd |= SPI_CMD_RX_DMA;
> + writel(cmd, mdata->base + SPI_CMD_REG);
> +
> + if (xfer->tx_buf)
> + mdata->tx_sgl = xfer->tx_sg.sgl;
> + if (xfer->rx_buf)
> + mdata->rx_sgl = xfer->rx_sg.sgl;
> +
> + if (mdata->tx_sgl) {
> + xfer->tx_dma = sg_dma_address(mdata->tx_sgl);
> + mdata->tx_sgl_len = sg_dma_len(mdata->tx_sgl);
> + }
> + if (mdata->rx_sgl) {
> + xfer->rx_dma = sg_dma_address(mdata->rx_sgl);
> + mdata->rx_sgl_len = sg_dma_len(mdata->rx_sgl);
> + }
> +
> + mtk_spi_update_mdata_len(master);
> + mtk_spi_setup_packet(master);
> + mtk_spi_setup_dma_addr(master, xfer);
> + mtk_spi_enable_transfer(master);
> +
> + return 1;
> +}
> +
> +static int mtk_spi_transfer_one(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + if (master->can_dma(master, spi, xfer))
> + return mtk_spi_dma_transfer(master, spi, xfer);
> + else
> + return mtk_spi_fifo_transfer(master, spi, xfer);
> +}
> +
> +static bool mtk_spi_can_dma(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + return xfer->len > MTK_SPI_MAX_FIFO_SIZE;
> +}
> +
> +static irqreturn_t mtk_spi_interrupt(int irq, void *dev_id)
> +{
> + u32 cmd, reg_val, i;
> + struct spi_master *master = dev_id;
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> + struct spi_transfer *trans = mdata->cur_transfer;
> +
> + reg_val = readl(mdata->base + SPI_STATUS0_REG);
> + if (reg_val & 0x2)
define 0x2?
> + mdata->state = MTK_SPI_PAUSED;
> + else
> + mdata->state = MTK_SPI_IDLE;
> +
> + if (!master->can_dma(master, master->cur_msg->spi, trans)) {
> + /* xfer len is not N*4 bytes every time in a transfer,
> + * but SPI_RX_DATA_REG must reads 4 bytes once,
> + * so rx buffer byte by byte.
> + */
> + if (trans->rx_buf) {
> + for (i = 0; i < mdata->xfer_len; i++) {
> + if (i % 4 == 0)
> + reg_val =
> + readl(mdata->base + SPI_RX_DATA_REG);
Strange indentation. Might be better to put readl on the same line,
and SPI_RX_DATA_REG on the next one.
> + *((u8 *)(trans->rx_buf + i)) =
> + (reg_val >> ((i % 4) * 8)) & 0xff;
This feels a bit awkward... Also, & 0xff is not needed.
> + }
> + }
> + spi_finalize_current_transfer(master);
> + return IRQ_HANDLED;
> + }
> +
> + if (mdata->tx_sgl)
> + trans->tx_dma += mdata->xfer_len;
> + if (mdata->rx_sgl)
> + trans->rx_dma += mdata->xfer_len;
> +
> + if (mdata->tx_sgl && (mdata->tx_sgl_len == 0)) {
> + mdata->tx_sgl = sg_next(mdata->tx_sgl);
> + if (mdata->tx_sgl) {
> + trans->tx_dma = sg_dma_address(mdata->tx_sgl);
> + mdata->tx_sgl_len = sg_dma_len(mdata->tx_sgl);
> + }
> + }
> + if (mdata->rx_sgl && (mdata->rx_sgl_len == 0)) {
> + mdata->rx_sgl = sg_next(mdata->rx_sgl);
> + if (mdata->rx_sgl) {
> + trans->rx_dma = sg_dma_address(mdata->rx_sgl);
> + mdata->rx_sgl_len = sg_dma_len(mdata->rx_sgl);
> + }
> + }
> +
> + if (!mdata->tx_sgl && !mdata->rx_sgl) {
> + /* spi disable dma */
> + cmd = readl(mdata->base + SPI_CMD_REG);
> + cmd &= ~SPI_CMD_TX_DMA;
> + cmd &= ~SPI_CMD_RX_DMA;
> + writel(cmd, mdata->base + SPI_CMD_REG);
> +
> + spi_finalize_current_transfer(master);
> + return IRQ_HANDLED;
> + }
> +
> + mtk_spi_update_mdata_len(master);
> + mtk_spi_setup_packet(master);
> + mtk_spi_setup_dma_addr(master, trans);
> + mtk_spi_enable_transfer(master);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int mtk_spi_probe(struct platform_device *pdev)
> +{
> + struct spi_master *master;
> + struct mtk_spi *mdata;
> + const struct of_device_id *of_id;
> + struct resource *res;
> + int irq, ret;
Space, not tab, between int and irq.
> +
> + master = spi_alloc_master(&pdev->dev, sizeof(*mdata));
> + if (!master) {
> + dev_err(&pdev->dev, "failed to alloc spi master\n");
> + return -ENOMEM;
> + }
> +
> + master->auto_runtime_pm = true;
> + master->dev.of_node = pdev->dev.of_node;
> + master->mode_bits = SPI_CPOL | SPI_CPHA;
> +
> + master->set_cs = mtk_spi_set_cs;
> + master->prepare_transfer_hardware = mtk_spi_prepare_hardware;
> + master->unprepare_transfer_hardware = mtk_spi_unprepare_hardware;
> + master->prepare_message = mtk_spi_prepare_message;
> + master->transfer_one = mtk_spi_transfer_one;
> + master->can_dma = mtk_spi_can_dma;
> +
> + of_id = of_match_node(mtk_spi_of_match, pdev->dev.of_node);
> + if (!of_id) {
> + dev_err(&pdev->dev, "failed to probe of_node\n");
> + ret = -EINVAL;
> + goto err_put_master;
> + }
> +
> + mdata = spi_master_get_devdata(master);
> + mdata->dev_comp = of_id->data;
> + if (mdata->dev_comp->must_tx)
> + master->flags = SPI_MASTER_MUST_TX;
> +
> + if (mdata->dev_comp->need_pad_sel) {
> + ret = of_property_read_u32(pdev->dev.of_node,
> + "mediatek,pad-select",
> + &mdata->pad_sel);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to read pad select: %d\n",
> + ret);
> + goto err_put_master;
> + }
> +
> + if (mdata->pad_sel > MT8173_SPI_MAX_PAD_SEL) {
> + dev_err(&pdev->dev, "wrong pad-select: %u\n",
> + mdata->pad_sel);
> + ret = -EINVAL;
> + goto err_put_master;
> + }
> + }
> +
> + platform_set_drvdata(pdev, master);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + ret = -ENODEV;
> + dev_err(&pdev->dev, "failed to determine base address\n");
> + goto err_put_master;
> + }
> +
> + mdata->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(mdata->base)) {
> + ret = PTR_ERR(mdata->base);
> + goto err_put_master;
> + }
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "failed to get irq (%d)\n", irq);
> + ret = irq;
> + goto err_put_master;
> + }
> +
> + if (!pdev->dev.dma_mask)
> + pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;
> +
> + ret = devm_request_irq(&pdev->dev, irq, mtk_spi_interrupt,
> + IRQF_TRIGGER_NONE, dev_name(&pdev->dev), master);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register irq (%d)\n", ret);
> + goto err_put_master;
> + }
> +
> + mdata->spi_clk = devm_clk_get(&pdev->dev, "spi-clk");
> + if (IS_ERR(mdata->spi_clk)) {
> + ret = PTR_ERR(mdata->spi_clk);
> + dev_err(&pdev->dev, "failed to get spi-clk: %d\n", ret);
> + goto err_put_master;
> + }
> +
> + mdata->parent_clk = devm_clk_get(&pdev->dev, "parent-clk");
> + if (IS_ERR(mdata->parent_clk)) {
> + ret = PTR_ERR(mdata->parent_clk);
> + dev_err(&pdev->dev, "failed to get parent-clk: %d\n", ret);
> + goto err_put_master;
> + }
> +
> + ret = clk_prepare_enable(mdata->spi_clk);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to enable spi_clk (%d)\n", ret);
> + goto err_put_master;
> + }
> +
> + ret = clk_set_parent(mdata->spi_clk, mdata->parent_clk);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to clk_set_parent (%d)\n", ret);
> + goto err_disable_clk;
> + }
> +
> + clk_disable_unprepare(mdata->spi_clk);
> +
> + pm_runtime_enable(&pdev->dev);
> +
> + ret = devm_spi_register_master(&pdev->dev, master);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register master (%d)\n", ret);
> + goto err_put_master;
> + }
> +
> + return 0;
> +
> +err_disable_clk:
> + clk_disable_unprepare(mdata->spi_clk);
> +err_put_master:
> + spi_master_put(master);
> +
> + return ret;
> +}
> +
> +static int mtk_spi_remove(struct platform_device *pdev)
> +{
> + struct spi_master *master = platform_get_drvdata(pdev);
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + pm_runtime_disable(&pdev->dev);
> +
> + mtk_spi_reset(mdata);
> + clk_disable_unprepare(mdata->spi_clk);
> + spi_master_put(master);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int mtk_spi_suspend(struct device *dev)
> +{
> + int ret;
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + ret = spi_master_suspend(master);
> + if (ret)
> + return ret;
> +
> + if (!pm_runtime_suspended(dev))
> + clk_disable_unprepare(mdata->spi_clk);
> +
> + return ret;
> +}
> +
> +static int mtk_spi_resume(struct device *dev)
> +{
> + int ret;
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + if (!pm_runtime_suspended(dev)) {
> + ret = clk_prepare_enable(mdata->spi_clk);
> + if (ret < 0)
> + return ret;
> + }
> +
> + ret = spi_master_resume(master);
> + if (ret < 0)
> + clk_disable_unprepare(mdata->spi_clk);
> +
> + return ret;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
> +#ifdef CONFIG_PM
> +static int mtk_spi_runtime_suspend(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + clk_disable_unprepare(mdata->spi_clk);
> +
> + return 0;
> +}
> +
> +static int mtk_spi_runtime_resume(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct mtk_spi *mdata = spi_master_get_devdata(master);
> +
> + return clk_prepare_enable(mdata->spi_clk);
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops mtk_spi_pm = {
> + SET_SYSTEM_SLEEP_PM_OPS(mtk_spi_suspend, mtk_spi_resume)
> + SET_RUNTIME_PM_OPS(mtk_spi_runtime_suspend,
> + mtk_spi_runtime_resume, NULL)
> +};
> +
> +struct platform_driver mtk_spi_driver = {
> + .driver = {
> + .name = "mtk-spi",
> + .pm = &mtk_spi_pm,
> + .of_match_table = mtk_spi_of_match,
> + },
> + .probe = mtk_spi_probe,
> + .remove = mtk_spi_remove,
> +};
> +
> +module_platform_driver(mtk_spi_driver);
> +
> +MODULE_DESCRIPTION("MTK SPI Controller driver");
> +MODULE_AUTHOR("Leilk Liu <leilk.liu@...iatek.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform: mtk_spi");
> diff --git a/include/linux/platform_data/spi-mt65xx.h b/include/linux/platform_data/spi-mt65xx.h
> new file mode 100644
> index 0000000..7512255
> --- /dev/null
> +++ b/include/linux/platform_data/spi-mt65xx.h
> @@ -0,0 +1,22 @@
> +/*
> + * MTK SPI bus driver definitions
> + *
> + * Copyright (c) 2015 MediaTek Inc.
> + * Author: Leilk Liu <leilk.liu@...iatek.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef ____LINUX_PLATFORM_DATA_SPI_MTK_H
> +#define ____LINUX_PLATFORM_DATA_SPI_MTK_H
> +
> +/* Board specific platform_data */
> +struct mtk_chip_config {
> + u32 tx_mlsb;
> + u32 rx_mlsb;
> + u32 tx_endian;
> + u32 rx_endian;
> +};
> +#endif
--
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